High-speed compressor



July 15, 1924 1501,5078

J, H. ,H. VOSS I HIGH SPEED COMPRESSOR L Filed Nov. 1921 2 Sheets-Sheet 1 Patented July 15, 1924.

" TED STATES JOHANN HEINRICH HERJIANN VOSS, OF NEW YORK, N. Y.

HIGH-SPEED COMPRESSOR.

Application filed November 2, 1921. Serial No. 512,269.

To all whom it may concern:

Be it known that I, JOHANN HEINRICH HERMANN Voss, a citizen of the United States of America, residing at 154 Nassau Street, New York, N. Y., have invented certain new and useful Improvements in High- Speed Compressors, of which the following is a specification. I

My invention relates to high-speed compressors for ammonia, sulphurous acid, metallic chloride, carbonic acid, air and other fluids.

My improved compressor comprises a gas tight crank case, high and low pressure cylinders provided with'differential pistons and connected with said crank case and means for forced lubrication through bores in the crank shaft to which are connected bores for supplying lubricant under pressure to the main and crank pin bearings. The connecting rods are provided with bores for supplying the gudgeon pins of the differential pistons with lubricant from the crank pins. I

Heretofore, compressors comprising a gas tight crank case were exclusively constructed for splash lubrication which, however, has the following drawbacks:

1. The lubricant becomes frothy by the continuous stirring.

2. It is drawn into the cylinders of the compressor, as during the suction stroke the pressure in the crank case exceeds that in the cylinders.

The consequence is that in compressors the number of revolutions of which is as low as 100 to 150 per minute, troubles through failure of lubrication frequently occur while at higher numbers of revolutions the oil is altogether drawn out of the crank case in a few hours, for instance, at the rate of 7 gallons in 8 hours, and passes into the condensing and vaporizing spaces of the refrigerating machine.

To overcome this drawback, I provide my improved compressor with differential istons which operate in two stages in hlgh by and low pressure cylinders. The cylinders are so arranged that only the high pressure cylinder is connected with the crank case. In this cylinder, even the suction pressure exceeds the pressure in the crank case. In consequence,'the lubricant which in the old compressors has a tendency to creep into the cylinder through the piston packing, here tends, on the contrary, to flow from the cylinder into the crankcase. This also facilitates greatly the separation of the small quantities of lubricant which are drawn along with the gas.

By this combination of differential pistons with high pressure cylinders and forced lubrication, it is possible to provide a high speed compressor which was impracticable heretofore. The same advantage is achieved where my improved compressor is used for compressing air. The high speed, the more effective lubrication and the facilitated separation of the oil are particularly important when compressing air for the purpose of obtaining its constituents, oxygen, etc. In this case, the low pressure cylinder may be provided with a cooling water jacket.

In the drawings aflixed to this specification and forming part thereof, a compressor embodying my invention is illustrated diagrammatically by way of example. In the drawings- Fig. 1 is a longitudinal section,

Fig. 2 is a 'cross' section of my improved compressor, taken on line 2-2 of Fig. 1,

Fig. 3 is a section of the valve chest on a larger scale, illustrating a modified valve construction.

The fluid to be compressed is drawn in through the suction pipe 1 by the low pressure pistons 6. The uid passes a suction valve 2 and a port 3 in the wall of the low pressure cylinders 3 and 4, respectively. Here, the fluid is compressed and forced through the delivery valves 8 of the low pressure cylinders to the suction valves 9 of the high pressure cylinders 7 which it enters through ports 10. The compressed fluid 1s forced into the delivery pipe 12 through the delivery valves 11 of the high pressure cylinders 7. The valves are of the annular plate type and inserted into a sleeve 13 which 1s divided underneath the delivery valve 8 of the low pressure cylinder. The valves, together with their seats, are inserted into the respective parts of the sleeve 13 connected a common screw bolt and firmly pressed on shoulders formed in said sleeve. The sleeve is ground into the valve chest and held by a yoke 14 on which pressure is e;- erted by means of a screw 15 supported in a threaded portion of the valve chest cover 16.

The valve arrangement illustrated in Fig. 3 differs from the one just described in that there are only three valvesinstead of four,

the delivery valve of the low pressure cylinder and the suction valve of the high pressure cylinder being combined into a valve 2'. i

The low pressure cylinders are insulated so as to maintain the suction gas in a cold and heavy conditionand the low pressure 'stage operates at a good volumetric efiiciency. The high pressure cvlinders are provided with cooling water jackets 19. The water in this jacket does not act on the suction gas which must be prevented, said gas being colder than the cooling water. Nor is it possible for the compressed gas to act on the suction gas and to heat it, as the delivery pipe is at a considerable distance from the suction pipe. As will appear it is prevented by all possible means that the suction gas absorbs heat from the walls which are in contact with the gas compressed to final pressure, which would reduce the volumetric efficiency. In high speed ammonia compressors for ice making machines the loss of volumetric efliciency owing to this cause is particularly high as an effective removal of the heat of compression and a reduction of that heat is counteracted by the fact that the cooling water for the compressed gas acts as a heating medium on the suction gas, this again increasing the heat of compression.

By the arrangement of differential pistons according to my invention, it is possibleto separate the hot and cold gases by very simple means, prevent heating of the suction gas and remove the heat of compression and friction which remains in the cylinder walls. The rapid removal of heat is particularly important at high speed and very effective in my improved compressor, as the circumference of the high pressure cylinders is completely surrounded by water.

The crank case 29 is gas tight and provided with covers 30 for inspection. Supported in the case is the crank shaft 20 with the crank pins 22 with which connecting rods 22 are cooperating. At the front end of the crank shaft, which, in the present instance, is rotated by an electromotor (not shown) of 20 H. P. at 600 revolutions per minute, is provided a stufling box 23, 24 which is placed on the crank case. The lubricant is supplied under pressure through the neck ring 25. The crank shaft is pro- 'ous modifications will occur to a person skilled in the art.

I claim:

1. In a stage compressor, in combination, a low and a high pressure cylinder, a stepped piston in said cylinders, means for reciprocating said pistons, a valve case connected with said cylinders, suction and delivery valves in said case, and means for supplying fluid to, and discharging fluid from said valve case, said low pressure cylinder being rovided with an insulatingjacket, and said high pressure cylinder with a cooling jacket.

2. In a stage compressor, in combination, a low pressure and a high pressure cylinder, a stepped piston in said cylinders, means for reciprocating said pistons, a valve case connected with said cylinders, suction and delivery valves in said case a cold suction pipe t one end, and a hot delivery pipe at the opposite end of said case, said low pressure cylinder being provided with an insulatin jacket, and said high pressure cylinder with a cooling acket.

'In testimony whereof I aflix my signature.

I JOHANN HEINRICH HERMANN VOSS. 

